This invention is directed to a novel cleaning composition for glassware. More particularly, the invention is directed to an anti-etch and cleaning composition that unexpectedly results in bottles that are substantially free of etching and contaminants after washing.
Glassware, like domestic dishes and glass bottles used in the soft drink and alcoholic beverage industries, is frequently rewashed, recycled and/or reused. With respect to glass bottles, for example, such a recycling process is extremely advantageous since it reduces the amount of glassware that, for instance, pollutes local neighborhoods and results in non-biodegradable debris in local landfills. Also, the recycling of bottles enables the beverage industry to save money by getting more uses out of the bottles it has invested in.
When recycling glassware, it is imperative that the glassware be washed to the point of being commercially sterile. Obtaining commercially sterile bottles, for example, from bottles that have been previously used, is not easy since used bottles are often contaminated with dirt, mold, sugar, food coloring, product labels, glue and the like. In order to remove such contaminants from the bottles being cleaned, harsh environments, such as those which employ relatively long contact times, high temperatures, chelators (e.g., ethylene diamine tetraacetic acid [EDTA] and nitrilotriacetic acid [NTA]) and caustic, are used. Such environments typically are successful in xe2x80x9ctransformingxe2x80x9d glassware that was once used into glassware that is substantially free of contaminants and commercially sterile.
Unfortunately, however, when bottles are subjected to harsh environments, like those that employ EDTA and NTA, the bottles begin to literally dissolve in the presence of the strong chelators. The dissolution of the glass gives the bottles a scratchy look, making the bottles aesthetically unappealing for consumer use. Moreover, glass dissolution results in free silica in cleaning environments. Free silica often creates problems in equipment used to clean glassware, since free silica often complexes with other materials and deposits as a silica scale on the equipment used for cleaning the glassware.
Other attempts have been made for cleaning glassware with compositions that do not employ harsh chelating agents like EDTA and NTA. These compositions typically use metal ions (e.g., zinc, beryllium); however, such compositions often do not display superior cleaning capabilities and can pose health, environmental and equipment problems.
It is of increasing interest to formulate a composition that results in glassware that is not etched, and contaminant free after washing. This invention, therefore, is directed to a superior anti-etch and cleaning composition that unexpectedly results in glassware, like bottles, that is substantially free of etching and contaminants after washing. Substantially free of contaminants is defined to mean glassware that is about as clean as glassware cleaned with conventional washing solutions, (having strong chelators like EDTA), as analyzed by the Examples which follow.
Efforts have been disclosed for cleaning glassware. In U.S. Pat. No. 5,849,095, anti-etch bottle washing solutions are made, and the solutions do not contain a phosphorus comprising polymer.
Other efforts have been disclosed for making cleaning compositions. In U.S. Pat. No. 5,622,569, a cleaning composition comprising sodium carbonate, sodium hydroxide and sodium gluconate is described.
Still further, other attempts for making cleaning compositions have been disclosed. In U.S. Pat. No. 5,084,198, thixotropic liquid dishwashing detergents that result in improved filming and spotting are described.
In a first embodiment, the present invention is directed to an anti-etch and cleaning composition comprising:
a) at least one polymer selected from the group consisting of a hetero functionalized polymer comprising a carboxylic acid group and a hetero functionalized polycarboxylate; and
b) caustic.
In a second embodiment, the present invention is directed to an anti-etch and cleaning composition comprising:
a) at least one polymer selected from the group consisting of a hetero functionalized polymer comprising a carboxylic acid group and a hetero functionalized polycarboxylate;
b) caustic; and
c) an anti-etch component.
In a third embodiment, the present invention is directed to glassware that has been subjected to the to the anti-etch and cleaning composition described in the first embodiment of this invention.
There generally is no limitation with respect to the type of hetero functionalized polymer comprising a carboxylic acid group that may be used in this invention other than that the polymer results in an anti-etch and cleaning composition that renders dirty glassware substantially free of etching and contaminants after washing. Such polymers typically comprise backbones that are derived from polypeptides, polyolefins, polyesters and polyethers, including homopolymers and copolymers (including terpolymers) prepared therefrom. The polymers also comprise carboxylic acid groups that are, for example, substituted on to the precursor monomeric units used to make each polymer.
There generally is no limitation with respect to the hetero functionalized polycarboxylate polymer used in this invention, other than that the polymer results in an anti-etch and cleaning composition that renders dirty glassware substantially free of etching and contaminants after washing. The preferred polycarboxylate polymers include those having hetero groups as grafts, terminating groups or both. The most preferred polycarboxylate polymers used in this invention are phosphino carboxylic acids and phosphono carboxylic acids having sulfonate groups, both of which are commercially available from FMC Corporation and sold under the names of Belclene 750 and Belclene 745, respectively. Other most preferred hetero functionalized polycarboxylate polymers which may be used in this invention include polymers having a portion derived from diacids. The most preferred diacid derived hetero functionalized polycarboxylate polymer used in this invention is one derived from the copolymerization of maleic acid, an alkyl acrylate (such as a C1-C4 alkyl acrylate) and a vinyl acetate. Such a terpolymer is commercially available from FMC Corporation and sold under the name of Belclene 730.
There generally is no limitation with respect to the hetero groups used to functionalize the polymers which may be used in this invention other than that the hetero groups enhance the solubility, chelating effect or both of the polymer. The preferred hetero groups are those comprising elements having a valence number of 5 or 6, with phosphino, phosphono and sulfonate groups being the most preferred hetero groups.
As to the hetero groups employed in this invention, such groups typically make up from about 0.1% to about 5.0%, and preferably, from about 0.15% to about 3.0%, and most preferably, from about 0.5% to about 1.5% by weight of the total weight of the hetero functionalized polymer comprising a carboxylic acid group or the hetero functionalized polycarboxylate, including all ranges subsumed herein. The primary factor with respect to determining the molecular weight of the hetero functionalized polymer used in this invention is the ability of the polymer to result in an anti-etch and cleaning composition able to achieve the desired results of this invention. Generally, however, the polymers have a weight average molecular weight ranging from about 500 to about 125,000.
When formulating the anti-etch and cleaning composition of this invention, there is no limitation with respect to the amount of hetero functionalized polymer used other than that the amount used results in a composition capable of achieving the desired results of this invention. Typically, the anti-etch and cleaning composition of this invention will have enough hetero functionalized polymer to produce an in use solution comprising from about 5 to about 5000, and preferably, from about 25 to about 3000, and most preferably, from about 250 to about 1200ppm hetero functionalized polymer. As used herein, in use solution is defined to mean the overall cleaning solution used in a conventional bottle cleaning system.
As to the caustic employed in this invention, there is no limitation with respect to the caustic employed as long as the caustic selected is one which results in an anti-etch and cleaning composition capable of achieving the desired results of this invention. Typically, however, the caustic employed is a Group IA or IIA hydroxide, ammonium hydroxide, or a mixture thereof. The preferred caustic is a hydroxide of sodium or potassium, with sodium hydroxide being the most preferred.
The amount of caustic employed is limited only to the extent that an anti-etch and cleaning composition may be formulated. Typically, the amount of caustic used is enough to result in an in use solution comprising from about 0.25% to about 20.0%, and preferably, from about 0.5% to about 15.0%, and most preferably, from about 1.0% to about 7.5% by weight caustic.
Regarding the anti-etch component used in the anti-etch and cleaning composition of this invention, such a component is preferred but optional and limited only to the extent that it may be used to prepare the desired composition of this invention. Typically, however, the anti-etch component employed in this invention is one comprising at least one carboxylic acid group. The preferred anti-etch component used in this invention is a polycarboxylic acid, (without a hetero group), and the most preferred anti-etch component is a polyacrylate, like a Group IA or IIA polyacrylate, with a sodium polyacrylate (e.g., Alcosperse 408, weight average molecular weight of about 3000, an anionic terpolymer made commercially available by Alco) being especially preferred.
The amount of anti-etch component employed in the anti-etch and cleaning composition of this invention is typically enough to result in an in use solution comprising from about 1.0 to about 1000, and preferably, from about 20.0 to about 500.0 and most preferably, from about 50.0 to about 150 ppm of the anti-etch component.
It is also within the scope of this invention to use conventional additives in the anti-etch and cleaning composition. Such additives include crystal growth inhibitors, like Acusol 505N or Acusol 479N, copolymers made commercially available from Rohm and Haas. Other additives include buffers, like sodium bicarbonate, sodium carbonate, sodium phosphate, sodium disilicate and mixtures thereof. Still further, other additives which may be employed in this invention include phosphonates (acids and salts) such as aminotri (methylene-phosphonic acid) and aminotri (methylene-phosphonic acid), pentasodium salt, both of which are sold under the name of DEQUEST 2000 and DEQUEST 2006, respectively and made commercially available by Solutia.
The amount of phosphonate that may be employed in the invention is often enough to produce an in use solution comprising from about 1 to about 2000, and preferably, from about 5 to about 1500, and most preferably, from about 50 to about 1100 ppm phosphonate.
Agents like gluconic acid and water soluble salts thereof may also be used in this invention to enhance the chelating action of the composition of this invention. Other agents that enhance the chelating action of the composition of this invention include an alkali metal glucoheptonate, alkali metal boroheptonate and mixtures thereof. Such agents that enhance chelating action typically result in an in use solution having from about 200 to about 2000 ppm chelating agent.
Still other additives which may be used in the anti-etch and cleaning composition of this invention include surfactants (e.g., anionic, nonionic and/or amphoteric). The nonionics may generally be classified as polyalkylglycosides. A preferred polyalkylgycoside is Glucopon 425CS, which is commercially available from Henkel Care Chemicals. Examples of other surfactants which may be used in this invention include sodium salts of carboxylated linear alcoholalkoxylates, lauryl sulfate, sodium xylene sulfonate, toluene sulfonic acid and salts thereof, sulfosuccinate salts, fatty acids and their salts, anionic glucoesters such as disodium cocoglucoside citrate, disodium cocoglucoside sulfosuccinate and sodim cocopolyglucose tartrate, iminodipropionates such as disodium tallow iminodipropionate, as well as disodium cocamphodiacetate and cocoamphocarboxylacinate, as well as disodium cocoamphodiacetate and cocoamphocarboxylacinate, and the imidazolines. It should be further noted that water may be added as the balance to the anti-etch and cleaning composition of this invention, if desired. A more detailed description of the additives which may be used in this invention may be found in U.S. Pat. 5,849,095, the disclosure of which is incorporated herein by reference.
As to the glassware which is subjected to the anti-etch and cleaning composition of this invention, such glassware is not limited and includes bottles from the soft drink and alcoholic beverage industries. Subjected to, as used herein, is defined to mean glassware that has been cleaned with the anti-etch and cleaning composition of this invention, whereby the cleaning takes place in conventional bottle washers.